The present invention relates to jewelry chains, specifically rope chains, and more particularly relates to a variation on an existing type of chain that is known as a "diamond cut rope chain".
A rope chain is a chain in the form of a rope constituted by a helical series of open rings or links that are interlinked with one another to define a configuration similar to a continuous double-stranded rope. Rope chains made of solid rings are simply known as rope chains while those made of hollow rings or links are known as "hollow rope chains".
The present invention is directed specifically to a type of rope chain to be known as a "spiral diamond cut rope chain" which derives from but provides a new look which differs from the conventional "diamond cut rope chain", to be discussed further on.
Methods for fabricating rope chains and machines therefor are known in the prior art as exemplified by the present inventors' U.S. Pat. No. 5,115,959, the contents of which are incorporated by reference herein. A thorough discussion of the conventional "diamond cut rope chain" is provided in U.S. Pat. No. 5,125,225, the contents of which are similarly incorporated by reference herein.
Prior machines of the general character indicated are described in U.S. Pat. Nos. 4,127,987 (Tega et al); 4,311,901 (Tega); and 4,503,664 (Allazzetta et al). Allazzetta et al is specifically directed to a machine by which the fabrication of rope chain is automated.
Additional patents dealing with the general subject matter include U.S. Pat. No. 4,716,750 of Tizzi, which discloses a machine for producing hollow articles with various tubular cross-sections. U.S. Pat. Nos. 2,424,924 and 2,711,069 describe methods of producing ornamental facets on solid wire chain links through grinding operations. U.S. Pat. Nos. 3,083,002 and 4,268,946 disclose the use of solidifying material such as ice, as a chuck to hold jewelry pieces in place while being worked on.
Further patents directed to the general subject matter include U.S. Pat. Nos. 2,895,290; 3,410,085; 4,679,391; 4,682,467; 4,681,664; 4,996,835; and German patent No. 2,428,642.
As previously noted, the present invention specifically concerns itself with the idea of providing a variation on the conventional diamond cut rope chain and to the construction and methods of fabricating the same.
As can be appreciated from the 5,125,225 patent, a "diamond cut" rope chain is a type of a chain in which the links of the chain are given a quality of sparkle by cutting or shearing away flat facets from the curved solid annular toroidal links, leaving flat surfaces for light to reflect therefrom. Diamond cutting of rope chains made of solid links is accomplished with a deep cut being used, so that from the generally round rope chain a four-faceted square or a six-faceted hexagon cross-section results. This way the "diamond cut" flat surfaces created in the solid chain gives an enhanced sparkling look to the chain.
In the 5,125,225 patent, the difficulty of forming a diamond cut rope chain of other than rope chains made of solid links is discussed. For example, it is noted that to achieve a square or hexagon cross-section chain, the depth of the cut has to be greater than the wall thickness of the annular, i.e. hollow, rings of which a hollow rope chain is made.
As recognized in the 5,125,225 patent (see the paragraph bridging columns 4 and 5 thereof), the prior art was familiar with various machinery and methods for creating hollow articles with various tubular cross-sections. The prior art was further familiar with various techniques of holding a pre-assembled chain in place by such methods as using a solidifying material, i.e. ice, as a chuck to hold the jewelry workpieces. Also noted is the familiarity of the art with stamping impressions into solid chain links and certain techniques for reinforcing hollow thin walled jewelry articles by electroforming. The 5,125,225 patent further recognizes and acknowledges the known use of both solid or hollow links in rope chains.
In view of the known teachings of the prior art, the 5,125,225 patent is specifically directed to a method for incrementally deforming curved hollow links to produce flattened faceted surfaces thereon. The subject patent is exclusively directed to the method involving the application of incremental pressure upon the curved wall surface of an otherwise fully assembled rope chain, thereby deforming the curved outer wall inward until a flattened "faceted" surface appears, similar to the faceted surfaces obtained by shearing/cutting rope chains formed of solid links. By carefully controlling the process of incremental deformations of the chain surfaces, a flat surface appearance which simulate the sheared or cut facet is obtained. It is also claimed that the deformed links of the chain have an increased resistance to fracture of the thin hollow link walls.
It is important to note that the process of the 5,125,225 patent is limited to creating a conventional "diamond cut" rope chain. In other words, as can be appreciated from a mere inspection of FIG. 11 of the subject patent, the burnishing tool used for creating the faceted surfaces is positioned to incrementally deform the chain while the chain is wound on a rotatable lathe. Completing one run of the burnishing tool over the length of the chain results in the formation of only a single facet (more precisely, a single line of sub-facets) on the chain. Since the typical diamond cut rope chain has a plurality of facets which are circumferentially spaced from one another, the chain has to be removed from the lathe and angularly rotated, for example, by 90.degree. three more times to create additional facets to produce a square shaped diamond cut rope chain. A smaller angular spacing is used if the number of facets is to be greater than four, etc.
It is obvious to one who appreciates the process of forming a conventional diamond cut rope chain that it is impossible to, for example, preform the individual links with deformed, flattened surfaces or to otherwise decorate the link surfaces to obtain a "conventional" diamond cut. This is because the conventional rope chain has a shape as shown in FIG. 8 of the subject 5,125,225 patent. Since the diamond cut requires that the surface be sheared to a certain depth relative to the longitudinal center of the chain, it will be immediately apparent that the individual links are not equally sheared or deformed. Rather, those links which are positioned more radially outwardly along the path of the faceted surface will be sheared or deformed to a greater extent than other links in the chain.
Since the links are differently sheared or deformed, it is impossible to preform them and later assemble them into a completed rope chain having the "conventional" diamond cut.
Further, while it might appear from the 5,125,225 patent that it is a straightforward matter to deform the hollow links of the rope chain with the help of a burnishing tool, it is perceived by the inventors herein that in practice the process may be far from simple. This is because it is essential that the chain be precisely placed on the lathe as shown in FIG. 11. If the links should not be perfectly aligned, it is possible that the burnishing tool will not engage and smoothly travel along the circumferential surfaces of the individual links. In such a case, the individual links might tear or be otherwise damaged.